Mr Maxwell Bloomfield1, Mr Tom Price2, Mr Nick Poole1, Ms Nicky Tesoriero3, Mr Rick Graham4, Mr Jordan Bathgate4,5, Ms Melissa Malone4, Dr Felicity Harris5, Ms Rebecca Smith6, Ms Sonja Seabrook6, Mr Todd McDonald7, Dr Karyn Reeves8, Dr Bonnie Flohr9, Dr Kenton Porker9, Dr Dane Thomas10,11, Ms Bronya Cooper10, Dr Peter Hayman10,11
1Field Applied Research Australia, Bannockburn, Australia, 2Field Applied Research Australia, Mulwala, Australia, 3Ceres Agronomy, West Beach, Australia, 4New South Wales Department of Primary Industries, Wagga Wagga, Australia, 5Charles Sturt University, Wagga Wagga, Australia, 6Living Farm, York, Australia, 7Frontier Farming Systems, Mildura, Australia, 8Department of Primary Industries and Regional Development, South Perth, Australia, 9Commonwealth Scientific and Industrial Research Organisation, Urrbrae, Australia, 10South Australian Research and Development Institute, Urrbrae, Australia, 11The University of Adelaide, Urrbrae, Australia
Biography:
Max is a research manager at Field Applied Research (FAR) Australia where he leads the national GRDC-funded project “Enhancing frost tolerance and/or avoidance in wheat, barley and canola crops through in-season agronomic manipulation”. Max also works across other projects focusing on sustainably and economically increasing yields of winter crops in farming systems across the high rainfall zones of Australia, with a particular focus on SW Victoria and SE South Australia.
Abstract:
Quick phenology wheat and barley cultivars are popular in Australia because they flower during the optimal period when sown and germinated in late April to mid May. However, early sowing of quick cultivars when germinating soil moisture is available increases frost risk as flowering occurs too early. Early sown slower cultivars can capitalise on early rainfall breaks and increase yields by flowering during the optimal period, but growers cannot access seed at short notice, nor have information on their performance from late emergence. Horticulturists and viticulturists prune apical meristems in perennial crops when development is too quick, and recent research has shown this method could delay flowering in early sown quick wheat while maintaining or increasing grain yield.
Guided by pre-experimental modelling we conducted time of sowing x defoliation intensity experiments on quick wheat and barley cultivars alongside untreated and slower phenology controls across five diverse agroecological zones. Defoliations delayed heading by 0-35 days and yields ranged from 1.34 t ha-1 less to 1.46 t ha-1 more than undefoliated controls when sown early. Slower phenology wheat cultivars typically out-yielded quicker cultivars when defoliation increased yield over the undefoliated control. The slower barley cultivar did not typically yield differently to the best defoliation treatments of the quicker cultivars.
These findings highlight the potential of late defoliation to delay flowering and mitigate frost risk without severe penalties to yield in early sown quick developing wheat and barley. Further research is required to identify and define the in-season signals and triggers that are most likely to warrant these practices.